Servers split into two clusters when deploying one cluster with multicast mode

I use 10 servers to deploy aerospike cluster. Ip list as follow:

10.21.82.145 
10.21.81.145 
10.21.81.144 
10.21.82.144 
10.21.82.147 
10.21.82.146 
10.21.82.141 
10.21.82.143 
10.21.81.143 
10.21.82.142

the config:

service {
    paxos-single-replica-limit 1 # Number of nodes where the replica count is automatically reduced to 1.
    proto-fd-max 15000
}
 
logging {
    file /home/admin/output/aerospike.log {
        context any info
    }
}
 
network {
    service {
        address any
        port 3000
    }
 
    heartbeat {
        mode multicast
        multicast-group 239.1.99.102
        port 9918
        mcast-ttl 5
        interval 150
        timeout 10
    }
 
    fabric {
        port 3001
    }
 
    info {
        port 3003
    }
}
 
namespace ns1 {
    replication-factor 2
    memory-size 100G
    default-ttl 90d
    high-water-memory-pct 80
    storage-engine device {
            device /dev/sda
            device /dev/sdb
            device /dev/sdc
            device /dev/sdd
            device /dev/sde
            device /dev/sdf
            scheduler-mode noop
            write-block-size 1M
        }
}

When I start all cluster nodes, i found the servers split into two cluster, one is orgnized with 10.21.81.(three nodes), another is orgnized with 10.21.82.(seven nodes)? Is something wrong with my configure? Or ?

See this post: Aerospike Cluster with multicast would be broken